Both frequency- and time-domain analyses of glide signals from a PZT glide-slider flying over a laser zone-textured (LZT) thin film disk medium were used to determine the slider vibration at a small disk-slider clearance. Slider vibration was found to be particularly dependent on the uniformly placed laser bump and the effects due to the air-bearing stiffness over the LZT medium. We found that a high density of small, pointed laser bumps (10X) has a more distinct impact on airflow than large, jagged-rim craterlike laser bumps (1X) on the slider. We therefore investigated the effect of laser bump density on the slider vibration, and found that marginally higher laser bump density (3X versus 2X) results in higher slider vibration. While resonant vibration has been a major glide problem, the effects of laser bump density have also recently become important in the face of ultralow glide height, 0.5 µ" (12 nm). Its influence can be clearly observed when the disk-slider clearance becomes very small. At such an ultrasmall disk-slider clearance, even minimal slider vibration can be detrimental to the head-disk interface. Taking into account the various contributions of slider vibration and considering possible damage to the head-disk interface, it is clear that the optimization of laser bump design should go beyond just the glide height and coefficient of stiction. It should take into account the effects of laser bump height, density and spatial distribution on vibration-induced flying height variation while maintaining a low glide height and coefficient of stiction. An ideal LZT medium should therefore have low bump height to enable low glide height, i. e. , 0.5 µ" (12 nm), but specific bump shapes and sufficient density to achieve low stiction. Laser bump density should, however, be controlled to moderate its effect on slider vibration and possibly disk-slider collision (297 words).